In a new radio access technology (NR) system, to support high-frequency wireless communication, impact caused by phase noise and switching of analog beams needs to be considered for resource configuration of a channel state information-reference signal (CSI-RS). A high-frequency wireless communication system uses spectrum resources in a high frequency band, to implement high-rate short-distance transmission and meet requirements on a 5G capacity and transmission rate. However, in the high-frequency wireless communications system, the phase noise is much less sensitive to frequency than to time, and to overcome a high path loss in the high frequency band, a physical layer needs to use a high-gain narrow beam antenna to improve coverage of a communications link. In such a process, the antenna may need to frequently switch between beams. The various factors described above require that a communications device complete channel measurement within a short period of time, to reduce the impact caused by the phase noise and impact caused to beam switching. Therefore, in the NR, it is considered to configure CSI-RSs in a same symbol (for example, an orthogonal frequency division multiplexing (OFDM) symbol).
On the other hand, as multi-antenna technologies develop, CSI-RSs at different antenna ports in a same network device may be multiplexed on a resource through code division, in other words, code division multiplexing (CDM). For example, the network device distinguishes between the different antenna ports by using different orthogonal cover codes (OCC). In the NR, to ensure that CSI-RSs at each antenna port are configured in a same symbol, resources of different antenna ports may be distinguished through frequency domain CDM, for example, frequency domain CDM2 and frequency domain CDM4. However, when a plurality of network devices send CSI-RSs by using a same antenna port and a same time-frequency resource, a same OCC code may be used. In this case, although the two CSI-RSs use different identifiers NIDCSI, the two CSI-RSs may still be strongly correlated and cause interference to each other.